Stretching machine for flattening metal strip



5 Sheets-Sheet l N. C. LAKE Filed Nov. 17, 1941 STRETCHING MACHINE FOR FLATTENING METAL STRIP Dec. 5, 1944.

Dec. 5 2,364,376

STRETGHING MACHINE FOR FLATTENING METAL STRIP N. C. LAKE s Sheets-Sheet 2 Filed NOV. 1'7, 1941 Dec. 5, .1944. N. c. LAKE 2,364,376

' STRETCH IN G MACHINE FOR FLATTENING METAL STRIP Filed Nov 17, 1941 5 Sheets-Sheet 5 Dec. 5, N. c. LAKE 2,364,376

STRETCHING MACHINE FOR FLATTENING METAL STRIP Filed Nov. 17, 1941 s'sheets-sheet 4 Dec, 5 19 N. c. LAKE STRETCHING MACHINE FOR FLATTENING METAL STRIP Filed Nov. '17, 1941 5 sheets-sneak 5 Patentcd Dec. 5, 1944 STRETCHING MACHINE FOR FLATTENING METAL STRIP Norman Cecil Lake, Stockton -on-Tees, England,

asslgnor to Head, Wrightson & Company, Limited, Thornaby-on-Tees, England Application November 17, 1941, Serial No. 419,483 In Great Britain September 24, 1940 6 Claims. (C1. 153-2) This invention relates to an improved stretching machine for flattening metal strip.

In the production of strip metal, particularly in the light alloys, it is often necessary to ensure absolute flatness, and since this cannot be obtained except by stretching, some form of stretching machine is required.

In the case of sheets, that is short strips, the stretching operation has long been accepted practice and there are various forms of sheet stretcher usually consisting of one gripper head moved backwards and forwards to fixed positions by means of screws and the other gripper head actuated by a hydraulic cylinder.

It is inconvenient to handle strips in the flat condition and therefore it is usual to arrange for. a strip to be coiled at the end of each operation, that is, rolling, pickling, washing, annealing, slitting and edge trimming, etc. This means that to stretch strip it is necessary to uncoil this and after stretching to re-coil it. It is known that this work is carried out in som works at the moment by uncoiling the strip as one operation,

and then transferring the strip to the stretcher after which it is passed to a coiler. Such a plant occupies a considerable amount of space and there is grave risk of mechanical damage to the strip owing to the excessive amount of handling.

The object of the present invention is to obviate excessive handling and to reduce the space required for effecting the operation. The machine according to the invention, whic receives as a coil the metal strip to be flattened, comprises a gripper head and uncoiling means working together so that as uncoiling of the coil of strip proceeds the uncoiling means and one gripper with the tail end of the strip in its grip are moved further apart, with the uncoiled strip held out between them, until the uncoiling has finished, whereupon the other end of the strip having been gripped by the other gripper, the two grippers co-operate to stretch the uncoiled strip and efiect the desired flattening. i Levelling means are provided through which the uncoiling strip passes as it travels from the coil to the gripper which is gripping the tail end of the strip. This gripper is preferably arranged so that it is caused to travel longitudinallyalong the bed of the machine synchronously with the uncoiling of the strip. Reversal of the travel of the gripper is effected as soon as the last portion of the uncoiled strip has been levelled and this causes the uncoiled strip to move so as to bring the free end of the strip into the other gripper. This other gripper is preferably the one which is caused to move to stretch the strip, the other gripper being anchored atan appropriate point in its path of travel.

After the strip has been stretched the machine strip in its grip with a movement synchronised with the recoiler.

The following is a description of the preferred construction of the machine according to the invention.

The invention is illustrated in the accompany ing drawings in which Figure l is a side elevation of one end portion of a complete machine, and Figure lis a side elevation of the other end portion of the machine, it being intended that Figures 1 and 1 be read as though the left hand end of Figure 1 were Joined to the right hand end of Figure 1. Figure 2 is a top plan of the end portion shown in Figure 1, and Figure 2 is a top plan of the end portion shown in Figure 1 it being understood that Figures 2 and 2 are to be read as though the left end of Figure 2 were joined to the right end of. Figure 2. Figures 3-8 are detail views "to a larger scale of the various component parts of the machine, Figure 3 being at the left hand side a sectional elevation on the line HI-III Figure 4 and on the right hand side a sectional elevation, Figure 4 being on the left hand side a sectional elevation on the line IVIV Figure 3 and on the right hand side an end elevation, Figure 5 being a sectional elevation, Figure 6 being a side elevation of the gripper head, and Figures 7 and 8 respectively plan and side elevations of mechanism provided for supporting, the s p.

The machine comprises a main bed ll, preferably of fabricated construction, on which is mounted a device indicated generally at 2 which may be called an uncoiler-leveller-recoiler. There .may also be mounted a conventional form of drum type uncoiler-coiler for use when thin gauge maybe my to stretch the strip to eifect the flattening which is required.

The uncoiler-leveller recoiler comprises two carrier rolls 1 for the coiled strip and a number or levelling rolls 3 the various rolls being driven by an electric motor 9 through gearing l3 and if necessary, a reducing worm gear II, the use of which depends on the speed operation which is decided upon. The various gear wheelslll terminate in universal connections 13 coupled by rods i3 having universal connections l4 to one of the ends of the various rolls to be driven.

The levelling rolls 3 are divided into anupper bank A and a lower bank B. The two can'ier rolls i and the upper levelling rolls A are mounted at their ends on spaced bearing blocks 13 and provided with robust guides l3 so as to permit vertical movement of the blocks Iland their rollers. The bearing blocks are counter-balanced by means, for example, of springs as shown at |'I or hydraulic cylinders, with suflicient stroke to leave the upper levelling rolls A well clear of the strip when the latter is being stretched between the two gripper heads 4 and 5.

The downward movement of the bearing blocks i5 is suitably effected by means of wedges l8 aetuatedby a ram and cylinder arrangement 19 operated pneumatically or by any other fluid pressure medium. To couple the ram to the wedges l8, the ram is provided with a rod 23 having on it a swivel block 2| engaged by a fork 22 on one arm of a lever 22' pivoted at 23 and the other arm of which is pivoted at 24 to a link pivoted at 23 to the wedge l8 at one end of the rollers and this wedge is itself connected to the other wedge I8. by a coupling rod 21; thus when the ram i9 is causedto move, the lever 22' is caused to rock and both wedges are move equally. The stroke of this ram l9 may be regulated by means of an adjustable stop so as to enable cor-v rect levelling of various gauges of material to be 7 obtained. This is effected by extending the rod 27 and securing toit a sleeve 23 having a flange 29 which in the limiting position engages a flange 33 on a collar 3| which is screw threaded to engage in a fixed threaded socket 32, the collar 3i having a hand-wheel 33 and a lock wheel 34 for the purpose of adjusting the position of the flange 30 and hence of the limiting position which is indicated on a scale 35.

One of the lower levelling rolls 13 (this being indicated at 9') is provided with an independent adjustment so that it will serve as a bending roll for the recoiling of the strip, The adjustment efiected bya worm and screw gearor by a screw and bevel gear or by a fluid-pressure cylin der having an adjustable stroke. For this purpose the roller 3' is independently mounted in blocks 33 fast with screwed rods 31 engaged by nuts 33 formed with a worm wheel 39 en aged by worms on a transverse operating spindle 40 so that when this spindle is rotated, the blocks -33 are adjusted vertically simultaneously.

Between the carrier rolls I there may be mounted a floor plate 4| having a number of idle rolls 4! and adjustable side guards 43 may be provided to centre the coil, these guards being adiusted by means of locking pins orv by screws .44, or by rack and pinion as preferred.

The drum type uncoiler-coiler 3 may be of conventional design provided with simple means of expansion and collapse and it is pr ferably overhung from a rigid bearing 43 and. is coupled. to an electric motor 43 by spur or worm gearing.

Declutching'means are provided'to enable the coilerto freewheei whilst uneoiling whilst the motor 43 is preferably of the variable speed type so as to permit a constant speed of coiling to be obtained in synchronism with the return travel oi the travelling gripper head.

Where the radial thickness of a complete cofl is not large relative to the diameter of the drum. a slipping clutch may be interposed in the drive so as to permit the drum to slip to compensate for the growth of the coil so as to enable the peripheral speed or the strip on the drum to synchronise with that of the levelling unit and the winch.

The gripper heads 4, 3 may be designed according to any of the known methods of gripping.

.though it is preferred to have gripper jaws of which is ambushed in the main hydraulic cylinder and the hollow bore of themainram 49.

The crosshead 48 which is coupled with the main ram 49 has a roller support 31 running on a track 32 formed as an extension of the bed I of the machine.

The return ram 53 may be under constant pressure and the main ram 49 operated by a single acting hydraulic valve, or alternatively both the return ram and the main ram may be operated by means of a double acting hydraulic valve.

The travelling gripper head 4 is mounted on ball or roller bearing rollers 33 and has an extension 34 formed to carry the fulcrum pin 55 on hooks 53 which are designed to anchor the travelling gripper head 4 during the stretching operation. The hooks are balanced by weights 31 and are provided with a latch mechanism 58 to support the hooks 55 in a position clear of the bed I when the gripper head 4 is travelling.

' The hooks 36 provide the anchorage by engagthe hooks 66 may be formed by placing two plates one above the other with their top faces together, the engaging surfaces being tumed'by means of a boring machine or other suitable tool. If necessary a distance piece may be placed between the plates in order to obtain the requisite amount of undercut.

For moving the travelling gripper head'4 there i employed a winch 3| driven by an electric motor 33 operating through a worm reduction gear, and a chain drive on to a back shaft. On this back shaft may be arranged two chain sprockets or rope drums carrying chains or ropes 33v attached to the travelling head 4 and then passing around return pulleys. V I

In order to avoid the possibility of mechanical damage due to the strap sagging between the I away from the uncoiler-leveller-recoiler 2 the cam 86 engages the various rollers 65 the cam 66 etfecting part of the movement of the arms and the movement being completed by the overcentre springs 69 which swing the various sup- 5 porting arms 64 across the bed beneath the strip to the position shown in Figure 7 this position being determined by stops Ill. The arms 84 are so arranged that on the return movement of the gripper head 4 they are pushed clear of the head this being effected by a roller II on the head 4 engaging the arms and the final position being determined by stops 1!. The tops of the supporting arms 64 may be faced with anti-scratching material and/orv rollers as shown at 13.

In operation, in the case of heavy strip, the coil is placed on the carrier rolls 1 of the uncoilerleveller-recoiler 2. The tail end of the strip is fed between the upper and lower banks A, B of the levelling rolls 8 which have been previously lowered under the action of the hydraulically or pneumatically operated wedges I8 working against the counterbalancing springs ll. The relative setting of the rolls will have been predetermined according to the gauge of material being operated upon.

The driving motor 9 is-then started and is run until sumcient material has been delivered to pass through the levelling rolls 8 into the travelling be necessary to bend the material by means of I gripper head I which will have been brought to reversed in motion so as to.feed the flattened end of material into the gripp r laws of the other head 5. The material will then be gripped and the bearing blocks l5 are raised by withdrawing the wedge operating devices i8 to raise the levelling rolls 8 of the upper bank A and the carrier rolls 1. Then the top of the bottom rolls-will be 1 clear of the strip.

Whilst this is being carried out another operator will be releasing the latch mechanism 58 to release the anchorage hooks 56 so that they drop into the nearest notches 59 in the bed i.

cylinder t forcing the main ram. '19 to pull the other gripper head t away from the travelling head i. The hydraulic ram 6 has sufl'icient stroke to enable the hooks 5G oi. gripper head 6 t be brought into engagement with the nearest locating notch 59 and also to stretch the strip to effects a the flattening required. When the books 58 have engaged with the suri'ace of the notches 59 the I head 4 will become stationary and the stretching c Hy- 5: draulic pressure will then be admitted to the strip from the head 5 and bring the end portion into the levelling rolls. The operation is stopped when material has passed the adjustable bending roll 8' and this roll is then raised to a predetermined position to give the desired diameter of coil and the motors 8 and 82 are started up so as to re-form the coil. As the travelling gripper head 4 approaches the end of its travel the machine will be stopped, the grip released and the coil finally formed. This coil will be lifted away and a further coil placed in position.

In the case of light gauge material this will be mounted on the drum type uncoiler-coiler 3. The drum will be expanded and the material fed by hand into the levelling rolls 8 when the cycle will be exactly similar to that described above. On completion of the stretching operation it will not the bending roll '8', but after release from the grippers in the gripper head 5 the material may be engaged in the driving slot of the drum so as to enable the coil to be reeformed.

The machine might be designed so as to allow the travelling gripper head 4 to be pulled back by means of the uncoiler-leveller-recoiler, but it is considered preferable to have a positive drive I for causing the gripper head i to travel in each direction since with thin gauge material resistance to motion of the travelling gripper head and its attendant parts may be sufllcient to over-stretch the material. In any case it is desirable that some form of slipping clutch be provided in the drive of the-winch 6i so as to compensate for any slight speed variation.

Various alternative methods may be employed for moving the travellin gripper head t. For instance the head may be attached to'a. heavy l nk chain or chains of sufiicient strength to withstand the stretching load. This would require to be provided with a heavy nonreversing drive also to withstand the load, although the motor operating this need not necessarily be of high power.

With this arrangement th provision of notches 59 in the bed would be avoided, but the overall expense would be considerably greater particularly when dealing with long lengths of strip, that is of the order of feet to feet.

It will be understood of course that many other modifications in the design and construction of the machine may be made within the scope of the invention.

. What I claim is: 1. In a machine for uncoiling, leveling, stretching and recoiling metal strip, means for supporting a coil of the strip for rotation; a leveling device comprising spaced pressure exerting roll means between which said strip is adapted to pass longitudinally; means mounting the pressure exerting roll means on one side of said strip for movement selectively towards and from the pressure exerting roll means on the other side of said will take placeand when the operator hasjudgedare then again started up so as to withdraw the 75 strip for respectively applying leveling pressure on said strip and for discontinuing the applicationof leveling pressure and thereby leaving said strip free to extend between the pressure applying roll means on opposite sides of the strip unrestrained by said pressure exerting roll means against longitudinal movement; a first gripper head; a second gripper head; means mounting said gripper heads respectively on opposite sides of said leveling device in the direction in which saidestrip passes through said leveling device: means for driving said pressure exerting roll means to unwind the strip from said coil and forward it to said first gripper head; mearm on 4. saidfirst gripper head for gripping the extended end of the thus forwarded strip; means for moving said first gripping head away from said leveling device while the strip is being moved between said pressure exerting roll means until said strip has been uncoiled and 'the opposite end portion of the strip has been leveled; means for reversing the drive to said pressure exerting roll means for moving said strip reversely and toward said second gripper head accompanied by reverse movement of said first gripper head with the gripping means thereon still gripping said strip extended end; means on said second gripping head for gripping said opposite end of said strip;.

2. In a machine for uncoiling, leveling, stretching and reeoiling metal strip, means for supporting a coil of the strip for rotation; a leveling device comprising spaced pressure exerting roll means between which said strip is adapted to pass longitudinally; means mounting the pressure exerting roll means on one side of said strip for movement selectively towards and from the pressure exerting roll means on the other side of said strip for respectively applying leveling pressure on said strip and for discontinuing the application of leveling pressure and thereby leaving said strip free to extend between the pressure applying roll means on op ite sides or the strip unrestrained by said pressure exerting roll means against longitudinal movement: a first per head;. a' second gripper head; means mounting said gripper heads respectively on opposite sides of said leveling device in the direction in which said strip passes through said leveling device; means for driving said pressure exerting roll means to unwind the strip from said coil and forward it tosaid first gripper head; means on said first gripper head for gripping the extended end of the thus forwarded strip; means for moving said first gripping head away from. said leveling device while the strip is being moved between said pressure exerting roll means until said strip has been uncoiled and the opposite end portion of the strip has been leveled; means for reversing the drive to said pressure exerting roll means for moving said strip reverseiy and toward said second gripper head accompanied by reversemovement of said first gripper head with the gripping means thereon still gripping said strip extended end; means on said second gripping head for gripping said opposite end of said strip; means for moving said movably mounted pressure exerting roll means away from the pressure exerting roll means on the other side of said strip to leave the strip free from restraint against longitudinal movement by said roll means; means for effecting relative separatingmovement of said gripper heads to stretch said strip; and

means for reeoiling said strip upon its being again fed through. said leveling device after at least one end of the strip has been released from the associated gripper head.

3. In a machine So;- uncoiling, leveling, stretching and reselling metal strip, means for supporting a coil of the strip for rotation; a leveling device comprising spaced pressure exerting roll means between which said strip is adapted to pass longitudinally; means mounting the pressure exerting roll means on one side of said strip for movement selectively towards and from the pressure exerting roll means on the other side of said strip for respectively applying leveling pressu 1n said strip and for discontinuing the applica'uan of leveling pressure and thereby leaving said strip free to extend between the pressure applying roll means on opposite sides of the strip unrestrained by said pressure exerting roll means against longitudinal movement; a first gripper head; a second gripper head; means mounting said gripper heads respectively on opposite sides of said leveling device in the direction in which said strip passes through said leveling device; means for driving said pressure exerting roll means to unwind the strip from said coil and forward it to said first gripper head; means on said first gripper head for gripping the extended end of the'thus forwarded strip; means for moving said first gripping head away from said leveling device while the strip is being moved between said pressure exerting roll means until said strip has been uncoiled and the opposite end portion of the strip has been leveled; an arm for supporting said strip; means mounting said arm for movement into and'out of the path of said first gripper head and into and out of supporting position with respect to said strip; means responsive to movement of said first gripper head during uncoiling of said strip for moving said am into strip supporting position between said-first gripper head and said leveling device; means for reversing the drive to said pressure exerting roll means for moving said strip reversely and toward said second gr pper head accompanied by reverse movement of said first ripper head with the gripping means thereon still gripping said strip extended end; means responsive to reverse movement of said first gripper head for moving said arm out of said strip supporting position; means on said second grippin head for grippin said opposite end of said strip; means for moving said movably mounted pressure exerting roll means away from the pressure exerting roll means on the other side of said strip'to leave the strip free from restrain against longitudinal movement by said roll means; means for efiecting relative separating movement of said gripper heads to stretch said strip; and means for reeoiling said strip upon its being again fed through said leveling device after at least one end of the strip has been released from the associated gripp r head.

4. In a machine for uncoiling, leveling, stretching and reeoiling metal strip, means for supporting a coil of the strip for rotation; first and second gripper heads mounted for movement in line with each other, and being adapted to grip opposite ends of a strip extending between said heads; a leveling device comprising roll means mutually opposed to engage opposite sides of the stripextending between said heads; the roll means on one side of the strip being positioned to leave the strip free to extend in a straight line between said heads and the roll means on the other side of the strip being mounted for move ment towards and from the strip for respectively engaging and being disengaged from said strip; means for driving said roll means forwardly s3 unwind the strip from the coil and forward it to said first gripper head; means for moving said first gripping head away from said leveling device while said strip is being thus moved and until said strip has been uncoiled and the opposite end portion of said strip has been leveled; means for reversing the drive to said roll meansfor moving said strip reversely toward said sec- 0nd gripper head accompanied by reverse movement of said first gripper head and movement of- -2,884,876 V a i a.

moving said one bank toward the other to bring said leveling rolls into feeding engagement with said strip opposite end into engagement with said second gripper head; means for moving said movably mounted roll means away from the strip; means for efiecting relative separation of said said strip, adjusting the position of one roll of one bank relatively to the remainder thereof,

and in returning said strip through the banks in feeding engagement therewith and recoiling it-on said means through the position and action of said one roll.

. 6. The method of uncoiling, stretching and recoiling a strip in one machine having coiling and uncoiling means and banks of leveling rolls, comrip r heads to stretch said strip; and. means tially through said banks in the opposite direction until the opposite-ends of the strip are disposed respectively on opposite sides of said banks, moving one bank away from the other to relieve the strip of rolling pressure, gripping the strip prising uncoiling a coil of the strip positioned on. said means by rolling passage through the o 7 banks in one direction, passing said strip pare tially through said banks in the opposite direction until the opposite ends of the strip are disposed respectively on opposite sides of said banks,

moving one bank away from the other to relieve the strip of rolling pressure, gripping the strip on opposite sides of said hanks while the strip extends through said banks, thereupon stretching on opposite sides of said banks while the strip extends through Said banks, thereupon stretching the strip, releasing the gripping of said strip,

the strip, releasing the gripping of said strip,- moving said one bank toward the other to bring said leveling rolls into feeding' engagement with said strip, driving said leveling rolls to feed said strip, and recoiling the strip as it is fed through said leveling rolls.

NORMAN CECIL LAKE. 

